Mark Henderson is Science Editor of The Times, having covered the beat for the paper since 2000. As well as winning prizes from the Medical Journalists' Association and the European School of Oncology for his news writing, he is a regular contributor to the op-ed pages and Eureka, the Times's monthly science supplement, which he helped to found a year ago. Mark is particularly known for his coverage of genetics and the political aspects of science. His first book, 50 Genetics Ideas You Really Need to Know, is published by Quercus. Here Mark writes about Carl Sagan's The Demon-Haunted World.
Mark Henderson on The Demon-Haunted World by Carl Sagan
The sceptical writer Michael Shermer likes to describe science not as a noun, but as a verb. It's a phrase that sounds a little clumsy to some people, but it speaks an important truth.
In the popular mind, science tends to be thought of in one of two ways. It is a collection of facts, of the sort we were all taught at school, a body of knowledge about the world. And it is a source of technology, from medicines to cars to computers, which change the way we live. Science is both of those things, but it is something else besides. It is also a method - an activity that people do to discover new truths, and to put them to use.
It is a rigorous approach to thinking, which derives hypotheses from observation, then seeks to put these to the test. It actively tries to prove itself wrong. It is not perfect by any stretch, but it is the best way humanity has yet devised of sorting what is so from what is not. To paraphrase Winston Churchill, it is the worst means of discovery, excepting all the others that have been tried from time to time.
If Shermer's metaphor explains this sceptical and self-correcting approach to knowledge in a soundbite, then Carl Sagan's The Demon-Haunted World does so as a hymn. Nearly 15 years after it was published, shortly before the great astronomer and popularizer of science died, it remains a remarkable and beautifully-written exposition of the value of science and what sets it apart from pseudo-science, anti-science and plain old baloney.
For Sagan, it is not sufficient to teach science as most of us learnt it in the classroom, through memorizing facts and performing experiments that are supposed to get a certain result. As citizens, we also need to understand how science reaches its conclusions, and how best to weigh the evidence upon which others' claims of truth are made; that 'science is more than a body of knowledge: it is a way of thinking'. He says:
If we teach only the findings and products of science - no matter how useful and even inspiring they may be - without communicating its critical method, how can the average person possibly distinguish science from pseudoscience? Both are then presented as unsupported assertion.
What follows is a tour through irrational and unfounded beliefs, from the witch-crazes of the Middle Ages to faith-healing and ESP. Sagan most thoroughly explores the paranormal phenomena which, as the world's most famous astronomer of his day, he most regularly encountered: UFOs and alien abductions. These, however, are but examples, with lessons that are perfectly applicable to contemporary failures of evidence-based thinking, such as the anti-vaccine movement and much alternative medicine.
As a primer in the scientific approach to problem-solving, it works magnificently. Sagan's explanation of how one might test his claim to have a fire-breathing dragon in his garage is particularly illuminating. He does something bigger, though, and more important than simply to dissect the evidence behind the weirdness. His voice is always one of compassion, that seeks not to mock but to understand why some people struggle with rational explanations of the world around them, and resort to the comfort of magic. He sounds a cautionary note to sceptics to beware cockiness, which all of us who care about critical thinking should bear in mind. Unbridled assault is rarely the best way to change minds.
The chief deficiency I see in the sceptical movement [he writes] is in its polarisation: Us vs Them - the sense that we have a monopoly on the truth; that those other people who believe in all these stupid doctrines are morons; that if you're sensible, you'll listen to us; and if you're not, you're beyond redemption. This is unconstructive. It condemns the sceptics to permanent minority status; whereas, a compassionate approach that from the beginning acknowledges the human roots of pseudoscience and superstition might be much more widely accepted.
Sagan is also magisterial on the serendipity of science, the way in which the pursuit of knowledge for curiosity's sake so often brings unexpected and thrilling spin-offs. His metaphor is the 'Westminster Project' - a grand imaginary scheme dreamt up by Queen Victoria to carry her voice across the Atlantic in real time, for which no resources would be spared. The initiative, he suggests, would have ended in failure. The equations devised by James Clerk Maxwell in the same era, with no practical purpose in mind, were however to realize an end that could never have been anticipated in advance. It is a point worth recalling whenever politicians seek to channel funding to research that will have economic or social impact.
As Bertrand Russell wrote: 'A habit of basing convictions upon evidence, and of giving to them only that degree of certainty which the evidence warrants, would, if it became general, cure most of the ills from which the world suffers.' The Demon-Haunted World is a book to form that habit.
[All the pieces that have appeared in this series, with the links to them, are listed in the index here.]